Fuel transfer pump



July 15, K, RABE 2,249,326

FUEL TRANSFER PUMP Filed Feb. 8, 1938 lNVENTOR ffar/ fYa/w Patented July 15, 1941 DFFUCE FUEL TRANSFER PUMP Karl Rabe, Stuttgart, Germany, assignor to Dr.

lng. h. c. F. Porsche, K.-G., Stuttgart-Zuffenhausen, Germany, a company of Germany Application February 8, 1938, Serial No. 189,286

*' In Germany February 16, 1937 6 Claims.

This invention pertains to fuel transfer pumps and particularly to such pumps commonly used on mot-or vehicles for transferring liquid fuel from a fuel tank to a carburetor or the like lo.- cated higher than the fuel tank and it has for an object to improve conventional pumps of this type by providing air venting means therefor.

In known fuel transfer pumps the suction space and the pressure space of the pump are not in direct communication. These prior constructions have the disadvantage that in the event the fuel tank as well as the usual filter vessel are completely emptied and thereafter the fuel tank is refilled with fuel, an air lock isformed in the suction conduit of the pump, which prevents the prompt filling of the pump, even though the Pump be located at a point lower than the fuel tank. For this reason it has heretofore been necessary to spin the motor repeatedly by means of the starter in order to eliminate the air lock, which places a great strain upon the electrical starter and upon the storage battery, with the result that in many cases it becomes inpossible to start the motor by means of the electrical starter.

It is an object of the present invention to overcome these disadvantages.

It is a more specific object to providein such pumps of otherwise conventional construction a passage communicating between the suction and delivery .conduits of the fuel transfer pump whereby air present in the suction conduit may pass into the delivery conduit and therethrough to the carburetor where itis allowed to escape to the atmosphere.

Other objects of the invention will become .apparent from the following description of one illustrative embodiment taken in connection with the attached drawing, wherein Fig. 1 discloses a fuel transfer pump, illustrating the invention, taken partly in section;

Fig. 2 is a cross-sectional view of a part of which casing is mounted. preferably in a conventional manner. displacement meanssuch as a diaphra m 2. the movement of which serves to periodically enlarge and decrease the volume in the pump chamber 16. The numeral 3 designates an intake valve of known or suitable construc- '5, the other end of which communicates with the carburetor or other fuel utilization 'device.

The intake valve 3 opens only when the diaphragm 2 of the fuel transfer pump is' moved, as, for example, by means of a cam, against the action of spring 5, viz'., in the direction of the arrow. Upon the occurrence of reverse movement of the diaphragm 2, the suction valve .closes and the delivery valve 6, which also is spring loaded, opens, and. thereby the way is open for the fiow of fuel' into the pressure conduit 1 of the fuel transfer pump. By means of the movement of the diaphragm 2 in the direction of the arrow, avacuum is created in the pump chamber H, which serves to move the intake valve 3. Upon the return movement of the diaphragm 2 the delivery valve 6 is opened. When the parts are at rest, the intake valve 3 as well as the delivery valve 6 are automatically closed.

The fuel transfer pump described thus far may be considered-as of conventional construction and as thus far described would have the disadvantages referred to above. However, it will be noted that the partition l0 shown as located between the delivery conduit 1 or between the pressure space 8 and the intake conduit 4 or the suction space "9 of the fuel transfer pump is provided with a passage i I as shown in Fig. 1 (or a plurality of passages lib as shown in Fig. 3) which provide a reliable escape of air from the intake pipe and the suction space 9 upon refilling the fuel tank, thus assuring the prompt resumption of operation of the fuel transfer pump after the tank is refilled.

Since in the construction shown there is a direct connection between the high pressure and the low pressure sides of the pump, a certain small amount of fuel will flow from the high pressure to the low pressure side. This is, how ever, not important since the passage II or passa es llb may be made very small and, furtherv more, because the amount of energy required on the other hand, the diaphragm 2 is held in continuous contact with the cam shaft and the development of noise in operation is avoided.

The invention is not limited to the form. of embodiment shown. It is unimportant whether for the purpose of permitting escape of the air one or more communicating passages are provided and whether they are located between the suction space or intake conduit and the pressure space or the delivery conduit. Furthermore, it is immaterial whether the communicating passage is formed as an exterior connection from the suction tothe pressure conduit of the fuel transfer pump or is provided within the pump body, if it makes possible within the sense of the invention an escape of air in the suction conduit to the pressure conduit.

Having described an illustrative embodiment of the invention it is pointed out that various changes and modifications therein may be made without departing from the invention as set forth in the following claims.

I claim:

1. In a pumping system, in combination, a liquid supply container, a pump located lower than said liquid container and having a pump chamber, an intake conduit connecting said liquid container with said pump chamber, an intake valve intermediate said intake conduit and said pump chamber, a delivery conduit, a delivery valve intermediate said delivery conduit and said pump chamber and an air vent connecting said intake and delivery conduits, whereby when liquid a delivery conduit connecting said receiver with said pump chamber, a delivery valve intermediate said delivery conduit and said pump chamber, and an air vent connecting said intake and delivery conduits, whereby when liquid is introduced into said container any air entrapped in said intake conduit may escape into said conduit and therethrough into said receiver so as to permit the liquid to reach and prime said pump, said vent being of such dimensions that only a negligible quantity of liquid will pass therethrough from the delivery conduit to the intake conduit when the pump is operating to pump liquid.

3. In a pumping system, in combination, a

pump having .a pump chamber, an intake conduit connecting said source of fluid to said pump chamber, a source of liquid under slight pressure, an intake valve intermediate said intake conduit and said pump chamber, a delivery conduit, a delivery valve intermediate said delivery conduit and said pump chamber, and an air vent connecting said intake and delivery conduits, whereby when liquid is admitted to said intake conduit any air entrapped in said intake conduit may escape into said delivery conduit so as to permit the liquid to reach and prime said pump, said vent being of such dimensions that is introduced into said container any air entrapped in said intake conduit may escape into said delivery conduit so as to permit the liquid to reach and prime said pump, said vent being of such-dimensions that only a negligible quantity of liquid will pass therethrough from the delivery conduit to the intake conduit when the pump is operating to pump liquid.

2. In a pumping system, in combination, a liquid supply container, 9. pump located lower than said liquid container and having a pump chamber, an intake conduit connecting said liquid container with said pump chamber, an intake valve intermediate said intake conduit and said pump chamber, a receiver for the pumped liquid,

only a negligible quantity of liquid will pass therethrough from the delivery conduit to the intake conduit when the pump is operating to pump liquid.

4. In a pumping system, in combination, a liquid supply container, 9. pump having a pump chamber, an intake conduit connecting said liquid container with 'said pump chamber, a source of liquid under slight pressure, an intake valve intermediate said intake conduit and said pump chamber, a delivery conduit, a delivery valve intermediate said delivery conduit, an air vent connecting said intake and delivery conduits, said air vent being located at a higher elevation than said intake conduit whereby when liquid is introduced into said container any air entrapped in said intake conduit may escape into said delivery conduit so as to permit tht liquid to reach and prime said pump, said vent being of such dimensions that only a negligible quantity of liquid'will pass therethrough from. the delivery conduit to the intake conduit when the pump is operating to pump liquid.

5. The combination according to claim 1 in combination with means for closing said air vent after the entrapped gas has escaped thtrethrough.

6. The combination .in accordance with claim 1 in which said vent consists of a plurality of relatively narrow communicating passages.

' KARL BABE. 

